Boat stabilizing unit



April 13, 1955 J. F. SHERRILL 3,177,837

BOAT STABILIZING- UNIT Filed Nov. 8, 1961 v 2 Sheets-Sheet 1 INVENTOR.

JOHN F. SHERRILL ATTO RNEY April 13, 1965 J. F. SHERRILL BOAT STABILIZING UNIT mmvrm iOHN E SHERRILL Filed NOV. 8, 1961 United States Patent 3,177,837 BOAT STABlLIZlNG UNIT John F. Sher-rill, Plymouth, Ind., assignor to Sea-Trim Corporation, Plymouth, Ind, a corporation of Indiana Filed Nov. 8, 1961, Ser. No. 151,044 7 Claims. (Cl. 114-665) This invention relates to improvements in boat stabilizing units.

The primary object of this invention is to provide a simple unit which is readily attached to a boat and which is efiective to stabilize the boat as it travels in the water.

A further object is to provide a boat stabilizing unit which is adjustable to compensate for different water conditions or waves.

A further object is to provide a device wherein plane members pivoted to the lower part of the transom of a boat are yieldingly urged to a predetermined downwardly rearwardly tilted position by means which applies progressively increasing resistance to upward pivoting of the plane members in response to reaction of the plane members with the water as the boat travels.

A further object is to provide a device of this character wherein plane members pivoted to the lower rear portion of a boat are urged to a predetermined downwardly rearwardly tilted limit position by means responsive to gas under pressure.

A further object is to provide a device of this character wherein plane members pivoted to the lower rear portion of a boat are controlled by means responsive to compressed gas in a system which includes means for regulating the gas pressure effective against plane members through said gas pressure responsive means.

A further object is to provide a device of this character wherein plane members pivoted to the lower part of the transom of a boat are controlled by pressure responsive members charged by a storage tank containing gas at high pressure, which tank is readily connected and disconnected, and wherein the gas pressure active upon the plane members is adjustable at the will of the operator.

Other objects will be apparent from the following specification.

In the drawings:

FIG. 1 is a fragmentary perspective view of the rear portion of a boat provided with my improved boat stabilizing unit;

FIG. 2 is a fragmentary side elevation of a boat equipped with my improved stabilizing unit, and illustratirig in dotted lines an operating position of the device difierent from that shown in full lines;

FIG. 3 is a schematic illustration of the control system incorporated in one embodiment of my invention;

FIG. 4 is an axial sectional View of a control valve for regulating gas pressure utilized in a control system forming a part ofmy improved boat stabilizing unit;

FIG. 5 is a schematic view illustrating a difierent control system associated with my boat stabilizing unit;

FIG. 6 is an assembly view illustrating another embodiment of my invention; 7 FIG. 7 is an enlarged fragmentary axial detail View illustrating a charging valve employed in conjunction with the embodiment of the invention illustrated in FIG. 6;

and

FIG. 8 is an axial sectional view of another form of pressure regulating valve usable in the stabilizing unit.

Referring to the drawings, and particularly to FIGS. 1 to 4 thereof which illustrate one embodiment of the invention, the numeral 10 designates a boat having a rear transom 12, sides 14 and bottom 16. The boat may be of any size, shape or design within a wide-range. As here illustrated, the boat is powered by an outboard 3,177,837 Patented Apr. 13, 1965 motor 18 mounted at the center of the transom thereof, but it will be understood that the boat may be powered by an inboard engine or by a jet engine or any other desired power means.

One or more rigid planes or plates 20, and preferably a pair of similar complementary planes or plates 20 are pivoted at one end by means of brackets 22 to the lower rear part, as the transom 12, of the boat. When two plates are used, they are preferably arranged in substantially equispaced relation to the central longitudinal axis of the boat with their respective pivot axes symmetrically arranged and extending transversely of the boat so that the two plates, when similarly positioned, will have the same or substantially the same, reaction with the water. The two plates 20 will preferably be spaced apart and cut away at their inner rear or free marginal portions when used with an outboard motor as shown.

An extensible and retractable strut carried by the transom is connected to each plate 20. In the form shown, a cylinder 24 is pivoted at one end thereof to a bracket 25 secured to the transom 12 spaced from the pivot axis of the adjacent plate. When two plates and two struts are employed, they are preferably similar in size and the brackets 25 are preferably equispaced from the vertical center of the transom and are arranged in similar and complementary relation to the adjacent plates 20. A piston 28 provided with suitable seals (not shown) is slidable in each cylinder; A piston rod 30 extends from each piston and has a sliding guided lit in an apertured end wall of the cylinder to project from the cylinder. The free end of each rod 30 is pivotally connected to a bracket 32 secured to the adjacent plate 20. The piston rods 30 are preferably of equal length so that the plates 20 will be positioned at the same angle when the pistons 28 occupy the same position lengthwise of their respective cylinders 24. Each cylinder 24 has a bleed or vent 34 formed therein at the end opposite the pivot bracket 26. Each cylinder 24 has an inlet port 35 adjacent its pivoted end.

When the plates 20 and the struts are mounted upon the boat, some means may be provided to limit the downward and forward swinging of the plates. Thus the parts may be so arranged that when the struts are fully extended, the plates 20 will assume a predetermined rearwardly downwardly tilting angle relative to the boat transom. The cylinders 24 are of such a length as to permit such piston travel therein as to permit the plates 20 to swing upwardly to approximately aligned relation to the bottom of the boat; that is, to approximately horizontal position when the pistons 24 are adjacent the upper ends of the cylinders.

Each cylinder 24- is connected with a source of gas under high pressure, such as a bottle or container 40, which preferably contains carbon dioxide or other gas which is preferably inert at high pressure. The charged gas container may be of any suitable type and may be charged to any pressure, such as 1000 p.s.i. In the form here shown, the container has an internally screwthreaded sleeve 42 arranged concentrically at one end thereof. An axial outlet passage 44 is formed in the end wall 46 of the container. The outlet passage 44 opens at a valve seat 43 which is normally engaged by a valve element 50 urged to closed or seated position by a spring 52-. Any suitable means (not shown) may be mounted in the boat 10 for detachably anchoring or positioning the gas container 40 conveniently and preferably near the transom 12.

.- A pressure regulator 56 of any suitable character,

adapted to regulate the-pressure in a line or conduit 53, e

is connected to the gas container 40. One form of such regulator is illustrated in FIG. 4 and comprises a cylin- Z drical housing 60 having a screw-threaded neck 62 at one end thereof adapted for releasable screw-threaded connection with the sleeve 42 of the gas container 40. A piston 64, having a suitable circumferential seal 66, is slidable in the housing 60. An axial plunger 68 projects from the piston 64 and passes slidably and with clearance through a bore 70 positioned axially in the end of the housing from which the neck projects and into the outlet passage 44 in the gas container 40, so that it is adapted to engage the valve element 50 to unseat the same when the piston 64 is at one end of its stroke. Regulator housing 60 has an outlet port 72 therein at the end thereof adjacent the neck 62. Line 58 is connected to the outlet port 72. The end wall 74 of the housing 60 mounted at the end opposite the neck 62 is suitably secured thereto as by means of securing screws 76. Wall 74 has a central screw-threaded aperture therein'within which is screwthreaded a thumb screw 78 preferably having a head or end 80 accommodating manual adjustment of the setting of the screw. The inner end of the screw bears against a plate or abutment 82. A coil spring 84 is positioned in the housing 60 between the cylinder 64 and the plate 82. The arrangement is preferably such that the setting of the screw 78 will permit regulation of the pressure which can exist in the line 58 at some value less than the'pressure in the tank 40, but adequate to cause functioning of the cylinders 24 to position plates while the boat is propelled.

The conduit 58 is connected with a regulating valve 86. A conduit 88 leads from the outlet of the valve 86, and one or more conduits 90 connect the conduit 88 with the inlet 36 of one or more of the cylinders 24. In the preferred form, one or more of the conduits 88 and 90 will be flexible to accommodate variation of the angular position of the cylinders 24 which occurs when the angular position of the plates 20 changes. A pressure gauge 92 communicates with the conduit 88 to permit determination of the pressure therein. An outlet conduit 94 preferably branches from the conduit 88 and has a manually operable bleed valve 96 associated therewith.

FIG. 3 illustrates an electrical control for the system. This control includes a circuit 100 which is preferably powered by a battery 102 and is under the control of a manually operable control switch 104. The circuit includes the coil 106 of a solenoid having a spring pressed stem or plunger 108 connected to the regulating valve 86. The valve 86 will normally be closed when the solenoid 106, 108 is inoperative and will be opened when the solenoid 106, 108 is energized. If desired, an electric lamp or other signal 110v may be connected in the circuit in parallel to the solenoid coil 106 to indicate the energized condition of the solenoid and hence the open condition of the regulator valve 86.

In the preferred form, the various control elements of the system may be incorporated in a control box 112. Thus the control box will preferably mount the pressure gauge 92 and the actuating means for the bleed valve 96 and the controlswitch 104.

In the use of the device. assuming that the plates 20 and the cylinders 24 are properly mounted upon the boat and that the various valves and conduits and gauges and the tank 40 are connected as illustrated in FIG. 3, and that the energizing circuit or control circuit 100 is operative, the device is conditioned for use by setting the screw 78 of the pressure regulator while valve 86 is closed. The regulator will be set to make available in the conduit 58,

,when said conduit and the regulator 56 are connected to the gas container 40, a supply of gas at a predetermined pressure in excess of that excepted to be required in the system and less than the pressure of the charge in the gas container 40, such as a pressure of from 50 to 300 p.s.i. Then the bleed valve 96 is' checked to insure that it is closed. Thereupon the switch '104 is closed to cause, opening of the valve 86 to permit gas under pressure to flow through conduits'88 and 90 to the respective cylinders 24.

4%. The setting of screw 78 regulates the extent of compression of spring 84 which acts on piston 64 to open valve to permit gas to flow from the tank 40 into the system. When gas pressure in line 58 and acting on piston 64 in the housing reaches a value exceeding the pressure exerted by spring 84, the piston moves in a direction to permit valve 50 to be closed by spring 52. The operator can ascertain the charge introduced into the cylinders 24 by observing the gauge 92 and, when a selected gas pressure is reached, he will open the switch 104 so that the regulator valve 86 is closed. When the switch 104 is closed to open the valve 86, pressure may drop in line 58 and in housing 60 below the piston 64, whereupon the spring 84 moves the piston to open the valve 50. Thus when pressure builds up in the regulator housing 60 below the piston 64 sufiicient to move the piston to compress the spring 84, the valve actuating plunger 70 is withdrawn from contact with the ball valve 50 which permits the ball valve 50 to seat. The piston 64 remains in plunger-withdrawing position as long as the pressure in conduit 58 remains high enough to flex spring 84.

The pressure in the cylinders 24 bearing against the pistons 28 serves normally to urge the plates 20 to a predetermined tilted limit position and to maintain the plates in that position as long as the boat remains stationary. The pressure utilized in the system may vary according to the wishes of the operator as determined by the size and shape of the boat, the expected speed of travel and the surface condition or wave pattern of the water. Under normal still-water conditions with small boats, a gas pressure of approximately 30 p.s.i. may be sufiicient to provide desired operation.

As the boat commences to move in response to the propellor or other means which drive it, the inclined or tilted plates 20 encounter water reaction and are subjected to forces tending to tilt the plates upwardly and thereby to move the pistons 28 upwardly in the cylinders 24. Since the valves 86 and 96 are both closed, upward movement of the pistons 28 in the cylinders 24 serves to compress the gas in said cylinders progressively. Thus it will be apparent that as the, speed of travel of the boat increases with resultant increase of the force of water reactance which tends to pivot the plates upwardly, a progressively increasing counter-pressure of the gas charge will tend to act in a direction to pivot the plates downwardly.

When proper gas pressure conditions exist within the cylinders 24, operation of the boat will cause the plates 20 to pivot upwardly to a position in which they assist in bringing the boat to a planing condition. Thus optimum speed of travel is achieved rapidly for any given setting of the engine throttle.

Another important characteristic of the device is that the plates 20 serve to maintain the boat in a stable condition in rough Water. One important characteristic which enables the stabilizer to accomplish this result i the fact that, as variations occur in the Water reactance encountered by the plates 20 due to wave action, the pivoted position of the plates is changed by the compression or expansion of gas in cylinders 24 to compensate for the wave action. Thus it has been found that the use of a stabilizing unit, as above described, upon a given boat will increase the safety and comfort of occupants of the boat, reduce slapping or pounding which frequently occurs in the use of. small boats in rough water, and will maintain a planing attitude of the boat as it moves through the water..

It will be observed that the manner in which a boat is trimmed and in which it acts in the water may vary according to the load as well as in accordance with water surface conditions. My stabilizing unit permits these variations to be accommodated by the simple expedient of changing the pressure acting upon the plates 20. Thus in cases where the loading of the boat is increased or decreased or where water surface conditions change by being either rougher or smoother, the operator may vary the operating pressure in the system in a manner to compensate for these changes. If increase in gas pressure in the system is required, the operator can close the switch 104 for the purpose of opening the regulating valve 86 to admit additional gas under pressure from the tank 40 to increase the operating pressure within the system. This change can be made in small steps or increments if desired, and the operator can observe the attitude and functioning of the boat after each step to determine when a proper charging pressure exists within the system. If the loading of the boat is reduced or a smoothing of the water surface occurs, so that the boat tends to porpoise, or otherwise acts in a manner indicating that a need exists to reduce the operating pressure within the system, the bleed valve 96 can be opened as desired to eifect reduction of the operating gas pressure in the system. The operator can observe the operating pressure in the system at all times by means of the gauge 92.

A modified embodiment of the invention is illustrated in FIG. 5, wherein parts similar to those employed in the embodiment illustrated in FIGS. 1 to 4 bear the same reference numerals. In this system the electrical circuit is omitted and a manually operable regulating valve 87 is interposed in the system between the conduits 58 and 88. It will be apparent that this system functions basically in the same manner as that illustrated in FIGS. 1 to 4.

Another embodiment of the invention is illustrated in FIGS. 6 and 7 which may be applied for individual control and charging of a unitary gas-charged member associated with an individual stabilizer plate 20. In this connection it will be apparent that one plate or more than two plates may be used upon a boat 10. In this form, the cylinder 24 has an inlet port 120 concentric with an internally threaded sleeve 122. An insert 124 having a central bore is screw-threaded in sleeve 122. The insert 124 has a valve seat 126 at its inner face and a conical recess 128 at its outer face. A valve member 130 is pressed against the valve seat 126 by a spring 132. Thus the inlet of the cylinder 24 is pro vided with a check valve. An outlet conduit 134 communicates with cylinder 24 adjacent the inlet port 120, and a manually operable bleed valve 136 controls the outlet conduit 134.

The charged gas container 46 has a conduit 140 connected at its outlet, which conduit communicates with a manually operable valve 142. The valve 142 communicates with a fitting 144 which preferably terminates in a conical tip 146 having a small diameter bore and a part-spherical end adapted to seat in the conical recess 128. If desired, the tip 146 may be formed of rubber or other resilient material. A pressure gauge 143 may communicate with the fitting 144 so that the operator can observe the pressure of the gas charge admitted into the cylinder 24. Alternatively, the pressure gauge 148 may be mounted upon the cylinder 24 or on the outlet line 134 between the cylinder 24' and the valve 136. The purpose of the gauge in any event will be to permit determination of the charge existing within the cylinder 24.

In the use of this embodiment of the invention, when it is desired to charge the cylinder 24, the gas charged container 40 with its associated fittings and parts 140, 142, 144 and 146 is held in a position as illustrated in FIG. 7 with the tip 146 pressed against the concave or recessed face 128 of the valve insert 124. Thereupon, the valve 142 is opened manually to the extent desired to permit discharge of gas at a selected rate from the container 40 through the fitting 144 and into the aperture of the valve insert 124 to unseat the check valve 126. As the charging operation continues, the user can observe the value of the gas charge upon the gauge 148 so as to determine when a desired pressure within the cylinder 24 is reached. Any overcharging of the cylinder can be bled by manipulation of the valve 136.

It will be apparent that this unit causes functioning of the boat stabilizing unit in the same manner described above insofar as regulation of the pivoting of the plate or plates 20 in response to water reactance pressures is concerned. This unit is suitable in all cases in which the operating conditions of the boat do not change greatly or in which a highly selective control of operating conditions is not deemed essential.

FIG. 8 illustrates an alternative construction of pressure regulator associated with gas container 40 for connection in a control system, as shown in FIG. 3, in place of the part 56 shown in FIG. 3. This regulator has a cylindrical body 160 with a screw-threaded cap 162 having a central screw-threaded aperture receiving an adjusting screw 164 which regulates the compression of a spring (not shown) within the body 160. A piston 166 has a circumferential seal 168 and is slidable in the body 160. The body has an axial passage 170 which communicates with a larger internally screwthreaded concentric opening to define a valve seat 172. A stem 174 carried by the piston 166 extends through the passage 170 with clearance and has an enlarged head 176. An annular gasket 178 preferably formed of Teflon or other tough material encircles the stem 174 and is adapted to be pressed to sealing engagement with the valve seat by the head 176. A fitting 180 having a bore therethrough is screw-threaded in the mouth of the body passage and projects therefrom. -The projecting part of fitting 180 is screw-threaded in the bore of the neck of container 40 and has a reduced end 182 of sufficient length to pass into the container 40 and unseat the valve thereof against the action of spring 52. The body 160 has an outlet port 184 at which conduit 58 is connected. 2

In this embodiment the gas pressure from the container 4% acts against piston 166 to move it to close valve 176, 173 at valve seat 172 when the pressure in conduit 58 exceeds the pressure for which the pressure regulator spring has been set. Subsequent reduction of pressure in line 58 permits reopening of the valve 176, 178 as required to'restore the desired operating pressure in conduit 58.

In all embodiments of the invention, it will be apparent that the charge of gas under pressure in cylinder 24 which is applied against pistons 28 to resist pivoting of the plates 20 in response to reaction with the water is further compressed by inward movement'of the pistons 28 in the cylinders and thus accomplishes progressive increaseof resistance as water pressure acting upon the plates increases and the plates pivot in response thereto.

Consequently, the device functions to compensate for variations in speed and variations in'water sur face conditions with the result that high operating efiiciency of the boat, high safety factors, and high comfort factors are achieved.

While the preferred embodiments of the invention have been illustrated and described, it will be understood that changes in construction may be made within the scope of the appended claims without departing from the spirit of the invention.

I claim:

1. In combination,

a boat having a transom,

a rigid plate pivoted at one end thereof to part of said transom, and

extensible strut means interconnecting said transom and plate spaced from said pivot and normally positioning said plate in rearwardly and downwardly the lower positions, said strut means including a cylinder andpiston, said cylinder containing a charge of gas under pressure acting on said piston to resist upward pivotal movement of said plate and means for charging said cylinder with gas under selected pressure.

2. In combination,

a boat having a transom,

a rigid plate pivoted at one end thereof to the lower part of said transom, and

extensible and contractible strut means containing a charge of gas under pressure to resist contraction thereof, said strut means being interposed between said transom and plate spaced from said pivot to normally position said plate in rearwardly ldownwardly inclined position and, means for charging said strutmeans with gas at selected pressure.

3. In combination,

a boat having a transom,

a rigid plate pivoted at one end thereof to the lower part of said transom,

an expansible and contractible plate-positioning strut member carried by said transom and spaced from said pivot plate,

a charge of compressed gas normally expanding said member,

a container charged with gas at high pressure,

conduit means connecting said container and expansible strut member, and

a regulating valve connected in said conduit means for regulating the pressure of gas supplied to said member from said container.

4. In combination,

a boat having a transom, a rigid plate pivoted at one end thereof to the lower part of said transom, an expansible and contractible plate-positioning strut member 'carired by said transom and spaced from said plate pivot,

a charge of compressed gas normally expanding said member,

a container charged with gas at high pressure,

a line connecting said container and expansible member,

a pressure regulator for controlling the pressure of gas supply from said container to said line, and

a regulable control valve in said line between said pressure regulator and said expansible strut member.

5. In combination,

a boat having a transom,

a rigid plate pivoted at one end thereof to the lowe part of said transom,

an expansible and contractible plate-positioning strut member carried by said transom spaced from said plate pivot,

a charge of compressed gas normally expanding said member,

a container charged with gas at high pressure,

a line connecting said container and expansible member,

a regulable control valve in said line operable to supply gas to and provide selected gas pressure in said expansible member, and

regulable means for bleeding gas from, said expansible member.

6. In combination,

a boat having a transom,

a pair of similar rigid water rectance plates pivoted to the lower portion of said transom in symmetrical relation,

a pair of struts carried by said transom and normally positioning said plates in a predetermined downward and rearward inclination, each strut including an expansible chamber,

a container charged with gas at high pressure, and

selectively actuated means connecting said container to said expansible strut chambers to charge said chambers with gas under selected pressure.

. In combination,

a boat having a transom,

a pair of similar rigid water rectance plates pivoted to the lower portion of said transom in symmetrical relation,

a pair of struts carried by said transom and normally positioning said plates in a predetermined downward and rearward inclination, each strut including an expansible chamber,

a container charged with gas at high pressure,

v means connecting said container to said expansible strut chambers to charge said chambers with gas under. pressure,

pressure regulating means for controlling the pressure of gas delivered to said chambers from said container, and

means for regulating pressure of the gas charge in said strut chambers.

References Cited by the Examiner UNITED STATES PATENTS 1,868,054 7/32 Easthope 114-665 1,875,135 8/32 Plum 114-665 2,576,744 11/51 Anderson 114-665 2,816,521 12/57 Alexander 114-665 2,958,486 11/60 Bloomfield et al. 114-665 2,985,130 5/61 'Jacobs et al. 114-66.5 3,001,499 9/61 Jacobs et a1 114-665 3,026,839 3/62 Fridge 114-665 3,046,928 7/62 Sherrill 114-665 FERGUS S. MZDDLETON, Primary Examiner. EMILE PAUL, Examiner. 

1. IN COMBINATION, A BOAT HAVING A TRANSOM, A RIGID PLATE PIVOTED AT ONE END THEREOF TO THE LOWER PART OF SAID TRANSOM, AND EXENSIBLE STRUT MEANS INTERCONNECTING SAID TRANSOM AND PLATE SPACED FROM SAID PIVOT AND NORMALLY POSITIONING SAID PLATE IN REARWARDLY AND DOWNWARDLY POSITIONS, SAID STRUT MEANS INCLUDING A CYLINDER AND PISTON, SAID CYLINDER CONTAINING A CHARGE OF GAS UNDER PRESSURE ACTING ON SAID PISTON TO RESIST UPWARD PIVOTAL MOVEMENT OF SAID PLATE AND MEANS FOR CHARGING SAID CYLINDER WITH GAS UNDER SELECTED PRESSURE. 